A brief review of the reflood closure package optimization efforts performed within TRAC 5.4.25R10

This report summarizes the implementation of tools within Version 5.4.25R10 of the Transient Reactor Analysis Code (TRAC); this implementation allows the semiautomated optimization of the reflood constitutive package. The tools included a software package external to TRAC that used a line search method to minimize a generic function value given the function`s partial derivative vector with respect to a set of closure coefficients used within TRAC`s reflood model. Within TRAC, the generic function was a normalized penalty function dependent on time averaged calculated values of vapor temperature, vapor void fraction, wall to a fluid heat transfer rate (or wall temperature), and the respective steady state data. The penalty function was implemented only for a one dimensional vessel configuration because the available reflood data were taken primarily from postcritical heat flux tube experiments.